London Mayor Ken Livingstone has called on Londoners and businesses to unite in the fight against global warming.
The mayor wants to cut emissions by 60% within 20 years
Unveiling his Climate Change Action Plan, the mayor appealed to people to stop wasting energy.
Londoners will be offered cut-price loft and cavity wall insulation and could cut £300 a year from fuel bills by making homes more energy-efficient.
He also urged companies to invest in green technology to help slash carbon emissions by 60% within 20 years.
By 2025 he wants 25% of London's electricity supply to be from local combined heat and power systems.
"Londoners don't have to reduce their quality of life to tackle climate change, but we do need to change the way we live," said Mr Livingstone.
"The present model of high energy production and high energy waste is utterly inefficient."
Without action, the city's carbon emissions will grow from 44 million tonnes a year to 52 million by 2025, he warned.
Environmentalists praised Mr Livingstone's action plans and urged the government to follow his lead.
Darren Johnson, Greeen Party memmber of the London Assembly, said "With the government allowing climate change emissions to rise since 1997, it is right that London should make the break with national complacency and declare that we will cut our emissions by 60% in the next 18 years, rather than the national target of 43 years."